I. Field
The present disclosure relates generally to communication, and more specifically to data transmission and power control in a communication system.
II. Background
A multiple-access communication system can concurrently communicate with multiple terminals on the forward and reverse links. The forward link, also referred to as the downlink, refers to the communication link from the base stations to the terminals, and the reverse link, also referred to as the uplink, refers to the communication link from the terminals to the base stations. Multiple terminals may simultaneously transmit data on the reverse link and/or receive data on the forward link. This is often achieved by multiplexing the multiple transmissions on each link to be orthogonal to one another in time, frequency and/or code domain. Complete orthogonality among the multiple transmissions is typically not achieved in most instances due to various factors such as channel conditions, receiver imperfections, and so on. Nevertheless, the orthogonal multiplexing ensures that the transmission for each terminal minimally interferes with the transmissions for the other terminals.
The number of terminals that may be served simultaneously on each link is typically limited by the number of traffic channels available for data transmission, which in turn is limited by the available system resources. For example, the number of traffic channels is often determined by the number of available orthogonal code sequences in a code division multiple access (CDMA) system, the number of available frequency subbands in a frequency division multiple access (FDMA) system, the number of available time slots in a time division multiple access (TDMA) system, and so on. In many instances, it is desirable to allow more terminals to transmit data simultaneously in order to improve system capacity.
There is therefore a need in the art for techniques to support simultaneous transmissions for more terminals in a multiple-access communication system.